Power Supply
Technical Information
1
Power
supp
lies
Power Supply
Technical Information
Power Supply Overview
■
What is a Power Supply?
Commercial AC power distributed from power plants cannot be
supplied directly to the ICs and other electronic components built
into electronic devices in automated office and factory equipment
without destroying the components due to the high voltage of
commercial AC power. Devices called power supplies or
regulated DC power supplies are therefore required to convert
commercial AC power into regulated DC power to drive ICs and
other electronic components.
■
Regulated DC Power Supplies
The methods for controlling Regulated DC Power Supplies can
be largely classified into the following two types. Switch-mode
power supplies and linear power supplies are generally referred
to as power supplies. Currently, switch-mode power supplies are
the most prevalent.
●
Switch-mode Power Supplies
Switch-mode power supplies convert commercial AC power into
the required high-frequency DC power using the high-speed
switching of semiconductors. Switch-mode power supplies are
so compact, light, and efficient that they are used as power
supplies by most electronic devices.
Advantages
Disadvantages
■
Power Supply Selection
●
Basic Selection Points
Factors to consider when selecting a Power Supply are provided
in the following diagram.
Switch-mode
Power
Supplies
Linear Power
Supplies
Regulated
DC Power
Supplies
Detection
circuit
Pulse width
modulator
Converts AC into DC
by rectifying and
smoothing AC.
DC OUT
AC IN
Steps down the voltage with a high-
frequency (40 to 200 kHz) transformer.
The primary and secondary sides are
insulated from each other.
Controls the high-frequency
switching pulse width and
frequency to stabilize the output.
•
Highly efficient.
•
Compact, and light.
•
A wide input voltage range.
•
Switching noise is generated.
•
Large inrush current on primary side.
(1) Input Voltage
Each Power
Supply has an
input voltage
range. Select the
Power Supply
according to the
available input
voltage.
(3) Safety Standards
Power Supplies
with UL, CSA, or
VDE approval, or
CE Marking are
available.
(4) Shape and Mounting Method
Power Supplies of various shapes
are available. Use the most
suitable Power Supply according to
the application. Various mounting
brackets are also available.
(2) Output Capacity (Voltage
×
Current)
The maximum load capacity must be
less than the maximum output
capacity of the Power Supply.
Power Supply
Load
